Fig. 7. Cell division defects and rescue of Prospero GMC expression. (A-F) Embryos stained for phosphorylated-histone H3 (brown). (C-F) Embryos also stained for prospero RNA (blue). (A-D) Ventral views of embryos shown at medium magnification; (E-F) sections of similar embryos shown at high magnification. The brackets in A,B indicate the ventral neurogenic region where most neuroblasts are located. There is clear staining of phosphorylated H3 in several cells in wild-type embryo (A), indicating mitosis. Much less staining is seen in the osp29 mutant embryo (B). Similar embryos double stained for prospero RNA showing the neuroblast layer (C,D). The arrowheads indicate some of the phosphorylated-H3 staining. Sections of similar embryos shown in E,F indicate that the neuroblast cell layer with prospero RNA staining also show mitosis occurring in wild-type embryos, but very rarely in osp29 embryos. The results suggest that the deletion mutants undergo less mitosis. (G,H) Staining of Prospero protein in GMCs. The expression of Prospero protein can be detected in many GMC nuclei along the two sides of the expanded midline in an embryo containing the string and inscuteable transgenes (H). The embryo containing the transgenes still has expanded midline, indicating the lack of Snail activity in blastoderm.